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    <title>trans</title>
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    <center>Scilab Function</center>
    <div align="right">Last update : 19/01/2006</div>
    <p>
      <b>trans</b> -  low-pass to other filter transform</p>
    <h3>
      <font color="blue">Calling Sequence</font>
    </h3>
    <dl>
      <dd>
        <tt>hzt=trans(hz,tr_type,frq)  </tt>
      </dd>
      <dd>
        <tt>hzt=trans(pd,zd,gd,tr_type,frq)  </tt>
      </dd>
    </dl>
    <h3>
      <font color="blue">Parameters</font>
    </h3>
    <ul>
      <li>
        <tt>
          <b>hz</b>
        </tt>: given fiter transfert function</li>
      <li>
        <tt>
          <b>pd</b>
        </tt>: Vector of given fiter poles</li>
      <li>
        <tt>
          <b>zd</b>
        </tt>: Vector of given fiter zeros</li>
      <li>
        <tt>
          <b>gd</b>
        </tt>: scalar: the given fiter gain</li>
      <li>
        <tt>
          <b>tr_type</b>
        </tt>: string, the type of transformation, see description for possible values </li>
      <li>
        <tt>
          <b>frq</b>
        </tt>: 2-vector of discrete cut-off frequencies (i.e.,<tt>
          <b>0&lt;frq&lt;.5</b>
        </tt>). For lp and hp filters only frq(1) is used. For bp and sb filters frq(1) is the lower cut-off frequency and frq(2) is the upper cut-off frequency. </li>
      <li>
        <tt>
          <b>hzt</b>
        </tt>: transformed filter transfert function.</li>
    </ul>
    <h3>
      <font color="blue">Description</font>
    </h3>
    <p>
    function for transforming standardized low-pass filter given its
      poles-zeros_gain representation into
    one of the following filters:
    </p>
    <p>
      low-pass ('lp'), the cutoff frequency is given by the first entry of frq,
      the second one is ignored
    </p>
    <p>
      high-pass ('hp'),  the cutoff frequency is given by the first entry of frq,
      the second one is ignored
    </p>
    <p>
      
      band-pass ('bp'), the frequency range is given by frq(1) and frq(2)
    </p>
    <p>
      stop-band ('sb') , the frequency range is given by frq(1) and frq(2).
    </p>
    <h3>
      <font color="blue">Examples</font>
    </h3>
    <pre>

clf()

Hlp=iir(3,'lp','ellip',[0.1 0],[.08 .03]);
subplot(311)
gainplot(Hlp,1d-3,0.48)
legend('original low pass')


Hbp=trans(Hlp,'bp',[0.01 0.1]);
subplot(312)
gainplot(Hbp,1d-3,0.48)
legend('band pass')


Hsb=trans(Hlp,'sb',[0.01 0.1])
subplot(313)
gainplot(Hsb,1d-3,0.48)
legend('stop band')


 
  </pre>
    <h3>
      <font color="blue">Author</font>
    </h3>
    <p>C. Bunks ;   </p>
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